PR debug/41438
	* dwarf2out.c (const_ok_for_output_1, const_ok_for_output): New
	functions.
	(mem_loc_descriptor, loc_descriptor, add_const_value_attribute): Bail
	out if !const_ok_for_output.

	PR debug/41474
	* dwarf2out.c (mem_loc_descriptor) <case CONCAT, case CONCATN,
	case VAR_LOCATION>: Remove gcc_unreachable ().

	* gcc.dg/debug/dwarf2/const-1.c: Add dg-require-visibility, make x
	hidden.
	* g++.dg/debug/dwarf2/const-1.C: Likewise.

From-SVN: r152282